The Vong had creatures that could hunt and kill Force users; voxyn. Anakin convinced Uncle Luke to let him lead a bunch of us on a mission to kill the Queen. The thing that was spawning them all.

( Her features lose all expression, and there's a faraway look in her brown eyes. )

Only nine of us survived. Anakin and Jacen didn't. There's... a place in my heart that's always been Jacen's. He's my twin. I felt a surge of pain, and then nothing.